A three-judge panel of the 9th U.S. Circuit Court of Appeals issued an emergency order putting the law on hold until the court can hear full arguments on the measure’s constitutionality. The law was set to take effect Jan. 1.

Licensed counselors who practice so-called "reparative therapy" and two families who say their teenage sons have benefited from it sought the injunction after a lower court judge refused the request.

The law, which was passed by the Legislature and signed by Gov. Jerry Brown this fall, states that therapists and counselors who use "sexual orientation change efforts" on clients under 18 would be engaging in unprofessional conduct and subject to discipline by state licensing boards.